Animals such as horses, cattle, pigs and the like that are kept indoors are generally fed at intervals with forage from wall mounted feeders or feeders raised above ground level including, feeding bowls, hay racks, mangers or hay-nets or from open buckets or other containers placed on the ground containing dry feed. Alternatively, forage is sometimes simply placed directly on the ground for the animal.
However, the above mentioned feeding methods and containers suffer from a number of disadvantages. Although the following drawbacks of known animal feeders are generally described in relation to a horse, it will be appreciated by those skilled in the art that similar or identical disadvantages are likely to be encountered with such feeders when used with other animals such as cattle, sheep, pigs and the like.
Wall mounted feeders such as hay-nets and the like must be positioned at a sufficient height so as not to reach ground level and create a hazard for a horse. In particular, hay-nets must be securely mounted in position and must not reach the ground when empty thereby further increasing the height at which the hay-net must be hung.
Importantly, all wall-mounted or raised feeders require an animal to feed in an unnatural non-grazing position i.e. above ground level—indeed wall mounted feeders can be mounted at heights of up to 1.0 to 2.0 resulting in severe muscular strain on the animal. Horses compelled to feed at a height can suffer from a misalignment or malocclusion of the upper and lower dental arcades leading to abnormal tooth wear patterns resulting in the development of cranial and caudal hooks on the teeth. For example, even in a standing position with the horse holding its head at approximately shoulder height, the teeth in the upper jaw protrude by approximately 2 mm over the teeth of the lower jaw giving rise to a highly unnatural non-grazing bite. Cranial and caudal hooks can lead to pain and considerable discomfort for the horse, nutritional deficiencies, behavioural abnormalities or deterioration in performance.
Feeding at a height places biomechanical stress on the animal at inter alia the head, neck and back and can contribute to musculoskeletal problems or stresses in these areas due to the unnaturally high head position. A horse with an elevated head carriage while feeding is therefore highly susceptible to thoracic, thoracolumbar and lumbar muscular strains due to sustained muscle contraction within these regions while chewing.
Feeding from elevated feeders also places additional stress on the temporomandibular joints, the atlanto-occipital and atlanto-axial joints and the associated musculature due to the twisting and rotating action of the horse's head as forage is pulled from the feeder.
Finally, although simply placing forage on the ground can replicate a natural grazing position, the forage quickly become soiled and inedible leading to wastage and potential underfeeding of the animal.
In general, due to their physiological make-up, grazing animals such as horses, cattle, sheep and like are habitual continuous grazers as opposed to interval feeders i.e. the animals exhibit a natural continuous grazing pattern. For example, horses in particular have a small stomach capacity (9-15 liters for the average horse) and a continuous natural grazing pattern provides a constant low volume trickle of forage through the stomach. Digestive acids are produced in the stomach irrespective of whether the horse is eating so that the absence of food in the stomach can result in the formation of gastric ulcers in the upper area of the stomach.
In general, known feeders only permit intermittent feeding of grazing animals e.g. known feeders are typically replenished at five to six hour intervals. Accordingly, where a stabled horse bolts its feed following replenishment of the feeder, the horse's stomach can be empty for prolonged periods resulting in an increased risk of ulcer formation.
Moreover, horses that bolt their feed, reduce the time spent chewing the feed, thereby compromising digestive efficiency which can also adversely affect digestion further down the gastrointestinal tract. For example, an average stabled horse chews 3,400 times/kg of forage and finishes eating forage in approximately 30-40 minutes for each feed. Accordingly, where the average horse is fed three times daily, no forage enters the horse's stomach for 22 hours in a 24 hour period. In addition, as the horse cannot then continuously graze in accordance with its natural instinct, the horse can become stressed and bored and suffer from physiological problems such as the aforementioned gastric ulcers and behavioural abnormalities such as crib-biting or wind-sucking.
More than 90% of racehorses in training have been reported to suffer from gastric ulcers which are one of the leading causes of impaired performance in the competition horse while non-competition horses such as foals and stabled horses in general are known to suffer from a high incidence ulcers. In contradistinction, a horse grazing in a field ad libitum has a natural mechanism of self-protection against gastric ulcers due to a continuous supply of forage passing into and through the stomach which, combined with the ongoing production of saliva during chewing, buffers the acidity of the digestive acids produced in the stomach.
Reducing the feeding interval with known feeders to reduce the incidence of ulcers is overly labour intensive while various more elaborate feeders known in the art fail to address the anatomical and physiological problems outlined above. For example, British Patent Specification No. 2,450,507 describes a feeder having a movable frame which moves downwards but not to ground level as food is removed or eaten so that the natural grazing position fails to be replicated.